Recovery of viscous crude oil



oct. 21, 1958 f E, F; PEVERE Emp 2,857,002

RECOVERY OF VISCOUS CRUDE OIL I Filed March 19, 1956 2 Sheets-Sheet 1 Oct. 2l, 1958 Filed March 19, 195e E. F, PEVERE ETAL RECOVERY oF vIscoUs CRUDE on.-

2 lSheets-Sheet 2 United AStates Ptent 851,002 RECOVERY or viscous CRUDE o1L nest F. Pevere, Beacon, and 'Herbert E. Vermillion,

Wappingers Falls, N. Y., assignorstto The Texas Company, New York, N. Y., `a corporation of Delaware Application March 19, 1956,seria1N0. 572,547 s claims. (cl. 16s-1) This invention relates to the recovery of viscous low gravity crude oil. More particularly,'this invention relates to a method for effecting improved and increased recovery of viscous low Agravity crude oil whereby the -resulting recovered oil has improved properties as evi-l perhaps the largest known commercial reserve of heavy crude. By present daycommercial methods of production, however, it has been estimated only a minoramount of the in-place oil is recoverable despite the fact that oil producing sand is relatively porous, about 30%, an'd possesses a relatively high average permeability of about 1300 md. The relatively low recovery of a'heavy viscous y crude from a producing sand containing the same is Vfor the most part due to the high viscosity ofthe in-place crude. In the San Ardo Field, for example, the viscosity of the in-place crude is'inthe range 25,000-300,000 Say-y bolt Universal seconds at 80 F. Also San Ardolcrude, as produced, has a pour point of about 55 F. In view of the extreme high viscosity of the in-place crude oil gas con'ing and water coning problems present themselves when production of a heavy crude is attempted. As a result, in order to avoid gas coning and/or water coning a viscous crude must be produced at a level substantially removed from'the gas cap and/or from the water table. For example, in producing crude from the San Ardo Field it has been the practice to vproduce from a level at least ice ` schematically illustrates one embodiment of the practice about '20 feet beneath the gas cap-andfrom a levelnot closer than Within 75 feet from the water table. Even' at these production levels, however, Yand despite a producing v formation thickness in some places of about 260 feet,

when increased rates of production are sought gas coning and/ or water coning problems are experienced.

Accordingly, `it is an object of this invention to provide -an improved method for the recovery of viscous crude oil from an underground formation containing the same.

Still another object of this invention is to provide av crude oil possesses improved properties as `a catalytic` f cracking charge stock. Y 1

How these and other objects of this invention are achieved will become more apparent with reference to the accompanying disclosure and drawing wherein Fig. 1

of this invention as appliedto a relatively shallow high viscosity heavy crude oil producing formation and wherein Fig. 2 schematically illustrates another embodiment of the practice of this invention as applied to a deeper viscous heavy crude oil producing formation.

In accordance with our invention an underground forviscous heavy crude present in' a relatively shallow underground formation 12, e. g., located not more than `at a depth of about 15.00 feet, a yshaft or borehole 11 is exca-` vated or drilled into the producing formation containing a viscous heavyl crude to be produced. vRadially out-4 wardly at diierent. levels from shaft 11 and inclined upwardly lwithin producing formation 12 there are drilled or driven a number of casings or pilings 14 which are lprovided with perforations 14a andllb. Disposed assoy ciated with orflocatedv within each of casings 14 is an electrical heating unit 15. Positioned within shaft 11 is production tubing 16 in communication with suitable sur.

face production equipment such as stock tanks, gasoil separators, settlers, treaters and the like, not shown. In accordance with a practice of this invention a hydrogencontaining gas such as the gaseous eflluent from a catalytic reformer containing associated normally gaseous` hydrocarbons such as methane, ethan'e, propane, butanes and the like or a hydrogenation plant or substantially pure f gaseous hydrogenis forced via shaft 11 and'casings through perforations 14a and 14h into producing formation 12 containing the Iviscous heavy crude oil to be treated and produced in' accordance with this invention.' During `passage through casing 14 the gaseous hydrogen stream is heated to a suitable elevated temperature by electrical.

heating means 15 which also acts to heat the producing formation surrounding lcasing 14 for a substantial dis- Upon contacting the heavy viscous crude withinA -the producing formation 12 the gaseous hydrogen reacts therewith an'd hydrogenatcs and tends to saturate the more. f chemcally-unsaturated and more-aromatic constituents of s the viscous heavy crude oil in situ. After hydrogenation t, of the viscouslreauv/yV crude oil the resulting hydrogenatedj, oil evidences asubstantially reduced viscosity and canfbe; produced viar perforations 14a and lMb and casing 14 intoV shaft. 11 from where-it is produced via production tance.

tubin'g` 16.

`As indicated in Fig. l of the drawing, the in situ hydrol `genationof the viscous heavy crude andthe production i of the resulting relatively less viscous hydrogenated crudefl can be carried out substantially simultaneously, the gase ous hydrogen preferentially entering producing formation 12 via perforation's 14a in the upper part .of casingsrli and the resultingl produced relatively less viscous hydrogenated crude preferentially entering casings 14 via the.Av

lower perforations 14h.

If desired, the inf situ hydrogenation Vof the heavy viscous-crude and the production of the resulting hydro@ genated crude can be carried out intermittently. In carry-j ing out intermittent hydrogenation of the heavy viscous,V crude and intermittent production of the relatively'less'r` viscous hydrogenated crude, a gaseous stream containing?` hydrogen (preferably containing at least 50% vol. H2)iisl i l"introduced into the formation 12 via shaft 11, casing-Fifi` and perforations 14a and 1411 for a substantial period of time and then permitted to remain'in contact with the viscous crude within producing formation 12 for a suitable time, for example, from raboutZvdays up to about 12 months, more or less, dependingr'lpon the volume of formation being treated, the viscosity and characteristics of the heavy viscous crude originally in-place and the properties desired in the resulting treated hydrogenated crude. After a suitable period of time the resulting hydrogenated crude is produced via performations 14a and Mb, casing 14 and production tubing 16.

Referring now to Fig. 2 ofthe drawing which schematically illustrates another embodiment of the practice of'this invention suitable for in situ hydrogenation of a relatively viscous heavy crude contained within a producing formation located at a relatively greater depth beneath the surface of the earth, such as a depth greater than about 3000 feet, more or less.

In accordance with the embodiment of this invention illustrated in Fig. 2 of the drawing, a number of directional boreholes extending substantially` horizontally are drilled within petroleum producing formation 31. Each of the directional boreholes is provided with a suitable casing 32 provided with perforations 32apand 32b. Each of the casings 32 is in communication with 4a central hydrogen supply casing 34 which is provided with a production tubing 35 which in turn is in communication at the surface with suitable production equipment, as described with reference to Fig. 1. As `indicated in the drawing, the lowermost casings 32 are advantageously inclined slightly upwardly from the horizontal within the producing formation 31. If desired, however, the' uppermost, lowermost and/or intermediate casingsl 32 may be substantially horizontal and parallel with respect tol each other or each inclined slightly upwardly in themanner illustrated in Fig. l of the drawing. v

In accordance with a practice of this invention as indicated in Fig. 2 of the drawing, a gaseous hydrogen stream is introduced into petroleum producing formation 31 via hydrogen supply casing 34, casings 32 and perforations 32a and 32h. As in Fig. 1 the in situ hydrogenation of the viscous heavy crude can be carried out substantially simultaneously with the production of the resulting hydrogenated 4crude or the hydrogenation of the in-place crude and the production of the .hydrogcnated crude can be carried out intermittently in the manner already indicated With reference to Fig. l.

In accordance with still another embodiment of the practice of this invention there is provided in the annular space between hydrogen supply casing 34 and production tubing 35 a suitable annular packer or gas sealing means 36. In accordance with this modified embodiment, hot 'gaseous hydrogen is introduced into the upper part of producing formation 31 via the upper casings 32 and resulting hydrogenated crude oil is produced from formation 31 via the lower producing casings 32.

The in situ hydrogenation of the viscous heavy crude within the petroleum producing formation is carried out under suitable hydrogenating conditions of'temperature and pressure. Usually a pressure in the range 500-5000 p; s. i. g., more or less, is a suitable hydrogenation pressure. The hydrogenation pressure should not exceed to any substantial extent the overburden pressure exerted on the producing formation undergoing treatment.

'Generally a hydrogenation temperature in the range 40G-1500" F., more or less, is suitable to elect the desired in situ hydrogenation of the viscous heavy crude.

The in situ hydrogenation reaction is carried out for a sufficiently long period of time to substantially reduce the viscosity of the in-place crude oil, e. g., to at least about 25% of its original capacity. Usually hydrogen consumption amounting to at least about 100 standardcubic feet (sc. f.) per barrel of oil originally in-place in that portionY of the formation undergoing treatment issufcient.,

The presence'of a hydrogenation catalyst in the hydrogen-containing stream introducede--intonthe formation undergoing treatment is desirable. Desirably the hydrogenation catalystis finely dispersed or otherwise vaporized within the hydrogen-containing gas being injected into the producing formation.; Particularly desirable as a hydrogenation catalyst is one which is normally gaseous under the temperature conditions employed during the in situ hydrogenation. Particularly useful as a hydrogenation catalyst is a halogen-containing material such as chlorine, bromine, iodine, hydrogen iodine, hydrogen bromide, bromoform, iodoform, methyl iodide, or any of the other well known, relatively volatile hydrogenation catalysts. In someinstances it will befunnecessary to incorporate a hydrogenation catalyst within the hydrogencontaining stream introduced into the petroleum producing formation because of the fact `that the producing formation undergoing treatment contains ores or other native minerals which exhibit hydrogenation catalytic activity, e. g., alumino-silicate clays, ores or minerals containing nickel-tungsten sulfide and the like.

The following examples are illustrative of the practice of this invention. i

EXAMPLE 1 A normally solid resin obtained by deasphaltingra sour West T exas-New Mexico fuel residuum and having a melting point of about 189 F. and a carbon residue of about 33% was charged to a high pressure bomb together with a small amount 'of a nickel-tungstenv sulde catalyst and gaseous hydrogen. A stepwise increase in temperature from about 400 F. indicated that the hydrogenation reaction was very slow below 650 F.

A temperature of 650 F. and avhydrogen pressure of 5000 p. s. i. g. was maintained upon the resin Within the bomb for about 10 months. 'During periodic inspections of the resin within the bomb-it was noted that the resin being hydrogenated gradually changed from a black solid to a dark green heavy liquid (at room temperature) and progressively became lighter `in color. After the end of the l0 month periodthe solid resin had been converted to a very light green oil having a gravity of 24.4 A. P. I. and a carbon residue of about 1.41%.

EXAMPLE 2 A sample of San Ardo crude admixed Awitl1'.0.10% by weight iodine as the hydrogenation catalyst was contacted with gaseous hydrogen at a temperature of 650 F. and a pressure of 5000 p. s. i. g. Within about hours under the above-identified hydrogenation conditions of temperature and pressure the crude oil had picked upv an amount of hydrogen equivalent to about 300 s. c. f. per barrel of oil. The A. P.I. gravity of the crude `had in-` creased from 12.1 to 17.0, therpour point was reduced from 65 E. to 0 F and the carbon residue-reduced-from about 9.9% to 5.9%.

EXAMPLE 3 A sample of San Ardo crude was hydrogenat'edv by contact with gaseous hydrogen at a temperature. of about 600 F. and at a pressure of 100,0 p. s. i. g'. fora period of about 65 hours until about` 300 s.Y c. f. of hydrogen yper barrel of crude was consumed, Tests on the originalv crude and the resulting hydrogenatedV crude are indicated in Table No. I.

Table No. l

Original Hydrogen- San Ardo ated San Crude Ardo Crude EXAMPLE 4 Further illustrative of the value of in situ hydrogenation for the recovery of a viscous heavy crude, 800 ccs. of -30 mesh sand were placed in a container and 350 grams of San Ardo crude were added so as to substantially fill all of the free space between the sand particles. The resulting admixture of sand and San Ardo crude together with about 2 grams of iodine was placed in a high pressure bomb, capacity 2600 cc., and the bomb ilushed with hydrogen. A hydrogenation reaction temperature of about 600 F. was maintained within the bomb but it was observed that the hydrogenation reaction at this temperature proceeded rather slowly. As a result, the hydrogenation reaction temperature was increased to 700 F. at which temperature the hydrogenation reaction proceeded quite rapidly. Two separate hydrogenation tests were carried out without agitation or mixing of the bomb contents, test No. 1 with the bomb in a horizontal position and test No. 2 with the bomb in a vertical position. After about 170 hours, an amount of hydrogen equivalent to about 300 s. c. f. per barrel of crude was consumed in test No. 1 and an amount of hydrogen equivalent to about 250 s. c. f. per barrel of crude was consumed in test No. 2. The resulting hydrogenated crude in each instance was recovered from the sand by washing with liquid isopentane, the isopentane being removed from the hydrogenated oil by distillation, and the resulting product examined. The results observed during the tests are set forth in Table No. 1I. Table No. II

As will be apparent to those skilled in the art, various substitutions, modifications and changes are possible without departing from the spirit or scope of this invention.

We claim:

1. A process for producing a viscous crude oil from an underground formation penetrated by a well bore, said crude oil having a viscosity at F. in the range 6,000- 400,000 Saybolt Universal seconds which comprises introducing gaseous hydrogen containing a vaporized volatile hydrogenation catalyst admixed therewith via said well bore into the upper portion of said formation, contacting said crude oil in situ in the upper portion of said formation with gaseous hydrogen at a temperature in the range 400- 1000 F. and at a pressure in the range 400-5000 p. s. i. g. to effect hydrogenation of said crude oil in situ, thereby producing a hydrogenated crude having a viscosity substantially reduced with respect to said crude, and subsequently producing the resulting hydrogenated crude from the lower portion of said formation via said well bore.

2. A process in accordance with claim 1 wherein the amount of hydrogen introduced into in situ contact with said crude oil and consumed during the in situ hydrogenation of said crude oil amounts to at least about standard cubic feet of hydrogen per barrel of crude oil in that portion of the formation undergoing treatment.

3. A process in accordance with claim 2 wherein the amount of hydrogen introduced into contact with said in situ crude oil is in the range 100-300 standard cubic feet of hydrogen per barrel of crude oil in that portion of the formation undergoing in situ hydrogenation and wherein said upper portion of said formation is maintained at an elevated temperature in the range 400-1000 F. by supplying heat thereto from an extraneous source.

References Cited in the iile of this patent UNITED STATES PATENTS 

1. A PROCESS FOR PRODUCING A VISCOUS CRUDE OIL FROM AN UNDERGROUND FORMATION PENETRATED BY A WELL BORE, SAID CRUDE OIL HAVING A VISCOSITY AT 80*F. IN THE RANGE 6,000400,000 SAYBOLT UNIVERSAL SECONDS WHICH INTRODUCING GASEOUS HYDROGEN CONTAINING A VAPORIZED VALATILE HYDROGENATION CATALYST ADMIXED THEREWITH VIA SAID WELL BORE INTO THE UPPER PORTION OF SAID FORMATION, CONTACTING SAID CRUDE OIL IN SITU IN THE UPPER PORTION OF SAID FORMATION 